Abstract: A fundamental problem in peer-to-peer networks is how to efficiently locate data. Decentralized data location is a novel approach to resolving this problem. However, the logic routing hops of all known decentralized data location algorithms are related to the number of nodes in networks, generally O（logn） or O（n 1/c）. Sifter is a scalable, fault-tolerant, self-organizing, efficient, and decentralized data location algorithm, in which each node maintains the linkage messages of other nodes of O（n 1/c） in networks so that it can locate any data identifiers within O（1） logic routing hops. This algorithm is particularly suitable for the network systems in which real-time of location is very important but dynamic property is negligible.